故障现象:康艺MV-5186彩电三无,指示灯不亮。检修过程:造成“三无”故障的主要原因:电源电路、行扫描电路。首先查电源电路,发现F_(501)、R_(503)烧断,C_(511)炸裂、Q_(504)击穿短路。将上述元件更新、断开行扫描电路,在主电源+B输出端,接一只100w灯泡做假负载,开机实测主电源为+170V,(远高于正常值+115V),并且不可调。继续查电源稳压电路,结果未见异常,用47uF/50V电容替换C_(501)后,主电源恢复正常,指示灯亮。但是,取下的电容用万用表测量,基本正 Symptom: Kang Yi MV-5186 TV three no light is not bright. Maintenance process: resulting in “three no” failure of the main reasons: power circuits, line scan circuit. First check the power circuit, found F_ (501), R_ (503) blown, C_ (511) burst, Q_ (504) breakdown short circuit. The above components update, disconnect the line scan circuit, the main power + B output, then a 100w bulb to do a dummy load, the measured power is + 170V, far higher than the normal value (+ 115V), and can not be adjusted. Continue to check the power regulator circuit, the result was no exception, with 47uF / 50V capacitor replacement C_ (501), the main power back to normal, the indicator light. However, remove the capacitance measured with a multimeter, the basic positive